It's kind of dumb right now. You have to select the pairs only or it won't work.It also can't handle selections with multiple instances of your separator. e.g. (key: "value:value=>" // this will melt your computer)Well I just wrote it down because I noticed I've been doing it a lot in PHP and I'm also trying to learn Python.You will notice my excitement in writing list comprehensions.

Below is an updated version that works in ST2. I basically updated the old code to use the new ST2 api and also fixed a bug that occurred if there was an empty line in your selection (failed when calculating the maxKeyLen).

Please note that I didn't write the original code and can't really speak for the completeness of this solution (I just updated it for fun and to get some more practice coding in python). For sure it does not consider your settings for tab_size or translate_tabs_to_spaces; it just blindly aligns the key-values using spaces. For a potentially more complete implementation, you might want to check out this: http://www.sublimetext.com/forum/viewtopic.php?f=5&t=2205&start=0.